The invention relates to an apparatus for exposure correction which may be used in a camera of automatic exposure control type, and more particularly, to such apparatus which provides a correction to an amount of exposure used in a camera of automatic exposure control type which is determined on the basis of an output from photometric means.
A camera of an automatic exposure control type generally adopts an average exposure scheme in which a mean value of the brightness of an object being photographed which is subject to photometry is reproduced as a median value of the film latitude. However, with this average exposure technique, a faithful reproduction is not achieved for an object being photographed, a major portion of which is occupied by a bright or dark area. Also, where the object being photographed exhibits an increased range of brightness, both a highlight and a shadow area are not reproduced (see FIG. 1).
Where the reproduction of tones in the highlight or shadow area is of importance, spotwise photometry is utilized to achieve a highlight or a shadow referenced exposure (see FIG. 1). A photographic camera which automatically enables such a highlight or a shadow referenced exposure is already proposed (U.S. Ser. No. 485,432).
In conducting the highlight of shadow referenced exposure, a shift from the average exposure should be changed in accordance with the film latitude. However, in practice, a uniform shift on the order of 2 EV is practically used so as to adapt with a reversal film having a relatively narrow film latitude. Consequently, the film latitude is not effectively used where a color negative film or a black-and-white film having a greater film latitude is used, leaving an increased zone out of reproduction. Specifically, referring to FIG. 2, it will be seen that an increased range of brightness (hatched portion) is left out of the reproduction when shifting to a narrower latitude R/2 than when shifting to a greater latitude R'/2.
Therefore it will be seen that in order to achieve the reproduction of proper tones in accordance with a particular film latitude, exposure factors may be determined by a manual operation of a photometer as has been done in the prior art practice. However this requires a troublesome procedure and is time consuming, and also disadvantageously requires a complicated calculation.